Thirteen Representatives (7 Democratic-Republicans and 6 Federalists) had been elected in 1796. One seat had changed from Federalist to Democratic-Republican in a special election in 1797. Two more seats, one held by a Democratic-Republican and one by a Federalist, had become vacant in August, 1798, and were still vacant at the time of the 1798 elections
Congressional districts
Pennsylvania was divided into 12 districts, one of which (the 4th) was a plural district, with 2 Representatives. These districts remained in use until redistricting after the census of 1800.
The counties that made up the 5th district did not border each other. That district was therefore made up of two separate pieces rather than being a single contiguous entity
Note: Many of these counties covered much larger areas than they do today, having since been divided into numerous counties. The boundaries of the districts are based on the counties' 1790 borders.
Election results
There were two vacancies and 11 incumbents at the time of the 1798 elections. The two vacancies were filled by special elections held at the same time as the general election. Blair McClenachan (DR) of the 2nd district and William Findley (DR) of the 11th district did not run for re-election. The remaining 9 incumbents (5 Democratic-Republicans and 4 Federalists) ran for re-election. 8 Democratic-Republicans and 5 Federalists were elected, a net increase of 1 seat for the Democratic-Republicans over the 1796 elections.